The present invention relates to a belt end connection for fastening a belt end in an elevator installation and to a method for protecting and checking a belt end connection in an elevator installation.
An elevator installation usually consists of a car and a counterweight, which are moved in opposite sense in an elevator shaft. The car and the counterweight are connected together and supported by means of support belts. One end of the support belt in that case is fastened by a belt end connection to the car or counterweight or in the elevator shaft. The location of the fastening is oriented to the form of construction of the elevator installation. The belt end connection accordingly has to transfer the force, which acts in the support belt, to the car or to the counterweight or to the elevator shaft. It thus has to be designed in such a manner that it can securely transfer the allowable load-bearing force of the belt. The direction of mounting of the belt end connection is oriented to the location of the fastening. If the belt end connection is mounted at the car or the counterweight a direction of tension of the support belt is usually oriented upwardly, but in the case of mounting of the belt end connection in the elevator shaft the direction of tension of the support belt is usually oriented downwardly.
In known constructions the support belt is usually fixed in a wedge pocket by means of a wedge. A first wedge pocket surface is in that case constructed in correspondence with the direction of tension of the support belt. This first wedge pocket surface is arranged in the direction of withdrawal of the support belt. A second bridge pocket surface is constructed to be displaced relative to the first wedge pocket surface in correspondence with a wedge angle of the wedge. The support belt is now arranged between the two wedge pocket surfaces and the wedge and it draws the belt, by virtue of the friction conditions, into the wedge pocket, whereby the support belt is fixedly clamped.
A belt end connection of that kind is shown in European Patent EP 1252086. A disadvantage of this construction is that the belt end connections are susceptible to damage, particularly since the wedge can, for example in the case of belt slack, slip out of the wedge pocket, whereby the support belt can be damaged or the belt end connection can be twisted, whereby higher levels of support belt loading result. Support belt damage and/or higher levels of loading can lead to failure of the support belt or to reduced serviceability of the elevator installation. Belt slack can result if, for example, the car or the counterweight is braked strongly or is braked to a stop, which can take place, for example, in the case of a test of safety brakes or in the case of travel of car or counterweight onto travel limiting devices. Twisting of the belt end connection can take place if the support belt experiences a twisting moment as a consequence of, for example, production tolerances of the support belt itself or as a consequence of arrangements of fastening and deflecting points. This torque causes twisting about a longitudinal axis of the belt end connection. The longitudinal axis corresponds with an effective direction of the support force acting in the support belt.